Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1383 insertions, 0 deletions

diff --git a/third_party/libwebrtc/rtc_base/virtual_socket_server.cc b/third_party/libwebrtc/rtc_base/virtual_socket_server.cc
new file mode 100644
index 0000000000..efc206b219
--- /dev/null
+++ b/third_party/libwebrtc/rtc_base/virtual_socket_server.cc
@@ -0,0 +1,1383 @@
+/*
+ *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "rtc_base/virtual_socket_server.h"
+
+#include <errno.h>
+#include <math.h>
+
+#include <map>
+#include <memory>
+#include <vector>
+
+#include "absl/algorithm/container.h"
+#include "api/units/time_delta.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/event.h"
+#include "rtc_base/fake_clock.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/physical_socket_server.h"
+#include "rtc_base/socket_address_pair.h"
+#include "rtc_base/thread.h"
+#include "rtc_base/time_utils.h"
+
+namespace rtc {
+
+using ::webrtc::MutexLock;
+using ::webrtc::TaskQueueBase;
+using ::webrtc::TimeDelta;
+
+#if defined(WEBRTC_WIN)
+const in_addr kInitialNextIPv4 = {{{0x01, 0, 0, 0}}};
+#else
+// This value is entirely arbitrary, hence the lack of concern about endianness.
+const in_addr kInitialNextIPv4 = {0x01000000};
+#endif
+// Starts at ::2 so as to not cause confusion with ::1.
+const in6_addr kInitialNextIPv6 = {
+    {{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2}}};
+
+const uint16_t kFirstEphemeralPort = 49152;
+const uint16_t kLastEphemeralPort = 65535;
+const uint16_t kEphemeralPortCount =
+    kLastEphemeralPort - kFirstEphemeralPort + 1;
+const uint32_t kDefaultNetworkCapacity = 64 * 1024;
+const uint32_t kDefaultTcpBufferSize = 32 * 1024;
+
+const uint32_t UDP_HEADER_SIZE = 28;  // IP + UDP headers
+const uint32_t TCP_HEADER_SIZE = 40;  // IP + TCP headers
+const uint32_t TCP_MSS = 1400;        // Maximum segment size
+
+// Note: The current algorithm doesn't work for sample sizes smaller than this.
+const int NUM_SAMPLES = 1000;
+
+// Packets are passed between sockets as messages.  We copy the data just like
+// the kernel does.
+class Packet {
+ public:
+  Packet(const char* data, size_t size, const SocketAddress& from)
+      : size_(size), consumed_(0), from_(from) {
+    RTC_DCHECK(nullptr != data);
+    data_ = new char[size_];
+    memcpy(data_, data, size_);
+  }
+
+  ~Packet() { delete[] data_; }
+
+  const char* data() const { return data_ + consumed_; }
+  size_t size() const { return size_ - consumed_; }
+  const SocketAddress& from() const { return from_; }
+
+  // Remove the first size bytes from the data.
+  void Consume(size_t size) {
+    RTC_DCHECK(size + consumed_ < size_);
+    consumed_ += size;
+  }
+
+ private:
+  char* data_;
+  size_t size_, consumed_;
+  SocketAddress from_;
+};
+
+VirtualSocket::VirtualSocket(VirtualSocketServer* server, int family, int type)
+    : server_(server),
+      type_(type),
+      state_(CS_CLOSED),
+      error_(0),
+      network_size_(0),
+      recv_buffer_size_(0),
+      bound_(false),
+      was_any_(false) {
+  RTC_DCHECK((type_ == SOCK_DGRAM) || (type_ == SOCK_STREAM));
+  server->SignalReadyToSend.connect(this,
+                                    &VirtualSocket::OnSocketServerReadyToSend);
+}
+
+VirtualSocket::~VirtualSocket() {
+  Close();
+}
+
+SocketAddress VirtualSocket::GetLocalAddress() const {
+  return local_addr_;
+}
+
+SocketAddress VirtualSocket::GetRemoteAddress() const {
+  return remote_addr_;
+}
+
+void VirtualSocket::SetLocalAddress(const SocketAddress& addr) {
+  local_addr_ = addr;
+}
+
+int VirtualSocket::Bind(const SocketAddress& addr) {
+  if (!local_addr_.IsNil()) {
+    error_ = EINVAL;
+    return -1;
+  }
+  local_addr_ = server_->AssignBindAddress(addr);
+  int result = server_->Bind(this, local_addr_);
+  if (result != 0) {
+    local_addr_.Clear();
+    error_ = EADDRINUSE;
+  } else {
+    bound_ = true;
+    was_any_ = addr.IsAnyIP();
+  }
+  return result;
+}
+
+int VirtualSocket::Connect(const SocketAddress& addr) {
+  return InitiateConnect(addr, true);
+}
+
+VirtualSocket::SafetyBlock::SafetyBlock(VirtualSocket* socket)
+    : socket_(*socket) {}
+
+VirtualSocket::SafetyBlock::~SafetyBlock() {
+  // Ensure `SetNotAlive` was called and there is nothing left to cleanup.
+  RTC_DCHECK(!alive_);
+  RTC_DCHECK(posted_connects_.empty());
+  RTC_DCHECK(recv_buffer_.empty());
+  RTC_DCHECK(!listen_queue_.has_value());
+}
+
+void VirtualSocket::SafetyBlock::SetNotAlive() {
+  VirtualSocketServer* const server = socket_.server_;
+  const SocketAddress& local_addr = socket_.local_addr_;
+
+  MutexLock lock(&mutex_);
+  // Cancel pending sockets
+  if (listen_queue_.has_value()) {
+    for (const SocketAddress& remote_addr : *listen_queue_) {
+      server->Disconnect(remote_addr);
+    }
+    listen_queue_ = absl::nullopt;
+  }
+
+  // Cancel potential connects
+  for (const SocketAddress& remote_addr : posted_connects_) {
+    // Lookup remote side.
+    VirtualSocket* lookup_socket =
+        server->LookupConnection(local_addr, remote_addr);
+    if (lookup_socket) {
+      // Server socket, remote side is a socket retreived by accept. Accepted
+      // sockets are not bound so we will not find it by looking in the
+      // bindings table.
+      server->Disconnect(lookup_socket);
+      server->RemoveConnection(local_addr, remote_addr);
+    } else {
+      server->Disconnect(remote_addr);
+    }
+  }
+  posted_connects_.clear();
+
+  recv_buffer_.clear();
+
+  alive_ = false;
+}
+
+void VirtualSocket::SafetyBlock::PostSignalReadEvent() {
+  if (pending_read_signal_event_) {
+    // Avoid posting multiple times.
+    return;
+  }
+
+  pending_read_signal_event_ = true;
+  rtc::scoped_refptr<SafetyBlock> safety(this);
+  socket_.server_->msg_queue_->PostTask(
+      [safety = std::move(safety)] { safety->MaybeSignalReadEvent(); });
+}
+
+void VirtualSocket::SafetyBlock::MaybeSignalReadEvent() {
+  {
+    MutexLock lock(&mutex_);
+    pending_read_signal_event_ = false;
+    if (!alive_ || recv_buffer_.empty()) {
+      return;
+    }
+  }
+  socket_.SignalReadEvent(&socket_);
+}
+
+int VirtualSocket::Close() {
+  if (!local_addr_.IsNil() && bound_) {
+    // Remove from the binding table.
+    server_->Unbind(local_addr_, this);
+    bound_ = false;
+  }
+
+  // Disconnect stream sockets
+  if (state_ == CS_CONNECTED && type_ == SOCK_STREAM) {
+    server_->Disconnect(local_addr_, remote_addr_);
+  }
+
+  safety_->SetNotAlive();
+
+  state_ = CS_CLOSED;
+  local_addr_.Clear();
+  remote_addr_.Clear();
+  return 0;
+}
+
+int VirtualSocket::Send(const void* pv, size_t cb) {
+  if (CS_CONNECTED != state_) {
+    error_ = ENOTCONN;
+    return -1;
+  }
+  if (SOCK_DGRAM == type_) {
+    return SendUdp(pv, cb, remote_addr_);
+  } else {
+    return SendTcp(pv, cb);
+  }
+}
+
+int VirtualSocket::SendTo(const void* pv,
+                          size_t cb,
+                          const SocketAddress& addr) {
+  if (SOCK_DGRAM == type_) {
+    return SendUdp(pv, cb, addr);
+  } else {
+    if (CS_CONNECTED != state_) {
+      error_ = ENOTCONN;
+      return -1;
+    }
+    return SendTcp(pv, cb);
+  }
+}
+
+int VirtualSocket::Recv(void* pv, size_t cb, int64_t* timestamp) {
+  SocketAddress addr;
+  return RecvFrom(pv, cb, &addr, timestamp);
+}
+
+int VirtualSocket::RecvFrom(void* pv,
+                            size_t cb,
+                            SocketAddress* paddr,
+                            int64_t* timestamp) {
+  if (timestamp) {
+    *timestamp = -1;
+  }
+
+  int data_read = safety_->RecvFrom(pv, cb, *paddr);
+  if (data_read < 0) {
+    error_ = EAGAIN;
+    return -1;
+  }
+
+  if (type_ == SOCK_STREAM) {
+    bool was_full = (recv_buffer_size_ == server_->recv_buffer_capacity());
+    recv_buffer_size_ -= data_read;
+    if (was_full) {
+      server_->SendTcp(remote_addr_);
+    }
+  }
+
+  return data_read;
+}
+
+int VirtualSocket::SafetyBlock::RecvFrom(void* buffer,
+                                         size_t size,
+                                         SocketAddress& addr) {
+  MutexLock lock(&mutex_);
+  // If we don't have a packet, then either error or wait for one to arrive.
+  if (recv_buffer_.empty()) {
+    return -1;
+  }
+
+  // Return the packet at the front of the queue.
+  Packet& packet = *recv_buffer_.front();
+  size_t data_read = std::min(size, packet.size());
+  memcpy(buffer, packet.data(), data_read);
+  addr = packet.from();
+
+  if (data_read < packet.size()) {
+    packet.Consume(data_read);
+  } else {
+    recv_buffer_.pop_front();
+  }
+
+  // To behave like a real socket, SignalReadEvent should fire if there's still
+  // data buffered.
+  if (!recv_buffer_.empty()) {
+    PostSignalReadEvent();
+  }
+
+  return data_read;
+}
+
+int VirtualSocket::Listen(int backlog) {
+  RTC_DCHECK(SOCK_STREAM == type_);
+  RTC_DCHECK(CS_CLOSED == state_);
+  if (local_addr_.IsNil()) {
+    error_ = EINVAL;
+    return -1;
+  }
+  safety_->Listen();
+  state_ = CS_CONNECTING;
+  return 0;
+}
+
+void VirtualSocket::SafetyBlock::Listen() {
+  MutexLock lock(&mutex_);
+  RTC_DCHECK(!listen_queue_.has_value());
+  listen_queue_.emplace();
+}
+
+VirtualSocket* VirtualSocket::Accept(SocketAddress* paddr) {
+  SafetyBlock::AcceptResult result = safety_->Accept();
+  if (result.error != 0) {
+    error_ = result.error;
+    return nullptr;
+  }
+  if (paddr) {
+    *paddr = result.remote_addr;
+  }
+  return result.socket.release();
+}
+
+VirtualSocket::SafetyBlock::AcceptResult VirtualSocket::SafetyBlock::Accept() {
+  AcceptResult result;
+  MutexLock lock(&mutex_);
+  RTC_DCHECK(alive_);
+  if (!listen_queue_.has_value()) {
+    result.error = EINVAL;
+    return result;
+  }
+  while (!listen_queue_->empty()) {
+    auto socket = std::make_unique<VirtualSocket>(socket_.server_, AF_INET,
+                                                  socket_.type_);
+
+    // Set the new local address to the same as this server socket.
+    socket->SetLocalAddress(socket_.local_addr_);
+    // Sockets made from a socket that 'was Any' need to inherit that.
+    socket->set_was_any(socket_.was_any());
+    SocketAddress remote_addr = listen_queue_->front();
+    listen_queue_->pop_front();
+    if (socket->InitiateConnect(remote_addr, false) != 0) {
+      continue;
+    }
+    socket->CompleteConnect(remote_addr);
+    result.socket = std::move(socket);
+    result.remote_addr = remote_addr;
+    return result;
+  }
+  result.error = EWOULDBLOCK;
+  return result;
+}
+
+int VirtualSocket::GetError() const {
+  return error_;
+}
+
+void VirtualSocket::SetError(int error) {
+  error_ = error;
+}
+
+Socket::ConnState VirtualSocket::GetState() const {
+  return state_;
+}
+
+int VirtualSocket::GetOption(Option opt, int* value) {
+  OptionsMap::const_iterator it = options_map_.find(opt);
+  if (it == options_map_.end()) {
+    return -1;
+  }
+  *value = it->second;
+  return 0;  // 0 is success to emulate getsockopt()
+}
+
+int VirtualSocket::SetOption(Option opt, int value) {
+  options_map_[opt] = value;
+  return 0;  // 0 is success to emulate setsockopt()
+}
+
+void VirtualSocket::PostPacket(TimeDelta delay,
+                               std::unique_ptr<Packet> packet) {
+  rtc::scoped_refptr<SafetyBlock> safety = safety_;
+  VirtualSocket* socket = this;
+  server_->msg_queue_->PostDelayedTask(
+      [safety = std::move(safety), socket,
+       packet = std::move(packet)]() mutable {
+        if (safety->AddPacket(std::move(packet))) {
+          socket->SignalReadEvent(socket);
+        }
+      },
+      delay);
+}
+
+bool VirtualSocket::SafetyBlock::AddPacket(std::unique_ptr<Packet> packet) {
+  MutexLock lock(&mutex_);
+  if (alive_) {
+    recv_buffer_.push_back(std::move(packet));
+  }
+  return alive_;
+}
+
+void VirtualSocket::PostConnect(TimeDelta delay,
+                                const SocketAddress& remote_addr) {
+  safety_->PostConnect(delay, remote_addr);
+}
+
+void VirtualSocket::SafetyBlock::PostConnect(TimeDelta delay,
+                                             const SocketAddress& remote_addr) {
+  rtc::scoped_refptr<SafetyBlock> safety(this);
+
+  MutexLock lock(&mutex_);
+  RTC_DCHECK(alive_);
+  // Save addresses of the pending connects to allow propertly disconnect them
+  // if socket closes before delayed task below runs.
+  // `posted_connects_` is an std::list, thus its iterators are valid while the
+  // element is in the list. It can be removed either in the `Connect` just
+  // below or by calling SetNotAlive function, thus inside `Connect` `it` should
+  // be valid when alive_ == true.
+  auto it = posted_connects_.insert(posted_connects_.end(), remote_addr);
+  auto task = [safety = std::move(safety), it] {
+    switch (safety->Connect(it)) {
+      case Signal::kNone:
+        break;
+      case Signal::kReadEvent:
+        safety->socket_.SignalReadEvent(&safety->socket_);
+        break;
+      case Signal::kConnectEvent:
+        safety->socket_.SignalConnectEvent(&safety->socket_);
+        break;
+    }
+  };
+  socket_.server_->msg_queue_->PostDelayedTask(std::move(task), delay);
+}
+
+VirtualSocket::SafetyBlock::Signal VirtualSocket::SafetyBlock::Connect(
+    VirtualSocket::SafetyBlock::PostedConnects::iterator remote_addr_it) {
+  MutexLock lock(&mutex_);
+  if (!alive_) {
+    return Signal::kNone;
+  }
+  RTC_DCHECK(!posted_connects_.empty());
+  SocketAddress remote_addr = *remote_addr_it;
+  posted_connects_.erase(remote_addr_it);
+
+  if (listen_queue_.has_value()) {
+    listen_queue_->push_back(remote_addr);
+    return Signal::kReadEvent;
+  }
+  if (socket_.type_ == SOCK_STREAM && socket_.state_ == CS_CONNECTING) {
+    socket_.CompleteConnect(remote_addr);
+    return Signal::kConnectEvent;
+  }
+  RTC_LOG(LS_VERBOSE) << "Socket at " << socket_.local_addr_.ToString()
+                      << " is not listening";
+  socket_.server_->Disconnect(remote_addr);
+  return Signal::kNone;
+}
+
+bool VirtualSocket::SafetyBlock::IsAlive() {
+  MutexLock lock(&mutex_);
+  return alive_;
+}
+
+void VirtualSocket::PostDisconnect(TimeDelta delay) {
+  // Posted task may outlive this. Use different name for `this` inside the task
+  // to avoid accidental unsafe `this->safety_` instead of safe `safety`
+  VirtualSocket* socket = this;
+  rtc::scoped_refptr<SafetyBlock> safety = safety_;
+  auto task = [safety = std::move(safety), socket] {
+    if (!safety->IsAlive()) {
+      return;
+    }
+    RTC_DCHECK_EQ(socket->type_, SOCK_STREAM);
+    if (socket->state_ == CS_CLOSED) {
+      return;
+    }
+    int error_to_signal = (socket->state_ == CS_CONNECTING) ? ECONNREFUSED : 0;
+    socket->state_ = CS_CLOSED;
+    socket->remote_addr_.Clear();
+    socket->SignalCloseEvent(socket, error_to_signal);
+  };
+  server_->msg_queue_->PostDelayedTask(std::move(task), delay);
+}
+
+int VirtualSocket::InitiateConnect(const SocketAddress& addr, bool use_delay) {
+  if (!remote_addr_.IsNil()) {
+    error_ = (CS_CONNECTED == state_) ? EISCONN : EINPROGRESS;
+    return -1;
+  }
+  if (local_addr_.IsNil()) {
+    // If there's no local address set, grab a random one in the correct AF.
+    int result = 0;
+    if (addr.ipaddr().family() == AF_INET) {
+      result = Bind(SocketAddress("0.0.0.0", 0));
+    } else if (addr.ipaddr().family() == AF_INET6) {
+      result = Bind(SocketAddress("::", 0));
+    }
+    if (result != 0) {
+      return result;
+    }
+  }
+  if (type_ == SOCK_DGRAM) {
+    remote_addr_ = addr;
+    state_ = CS_CONNECTED;
+  } else {
+    int result = server_->Connect(this, addr, use_delay);
+    if (result != 0) {
+      error_ = EHOSTUNREACH;
+      return -1;
+    }
+    state_ = CS_CONNECTING;
+  }
+  return 0;
+}
+
+void VirtualSocket::CompleteConnect(const SocketAddress& addr) {
+  RTC_DCHECK(CS_CONNECTING == state_);
+  remote_addr_ = addr;
+  state_ = CS_CONNECTED;
+  server_->AddConnection(remote_addr_, local_addr_, this);
+}
+
+int VirtualSocket::SendUdp(const void* pv,
+                           size_t cb,
+                           const SocketAddress& addr) {
+  // If we have not been assigned a local port, then get one.
+  if (local_addr_.IsNil()) {
+    local_addr_ = server_->AssignBindAddress(
+        EmptySocketAddressWithFamily(addr.ipaddr().family()));
+    int result = server_->Bind(this, local_addr_);
+    if (result != 0) {
+      local_addr_.Clear();
+      error_ = EADDRINUSE;
+      return result;
+    }
+  }
+
+  // Send the data in a message to the appropriate socket.
+  return server_->SendUdp(this, static_cast<const char*>(pv), cb, addr);
+}
+
+int VirtualSocket::SendTcp(const void* pv, size_t cb) {
+  size_t capacity = server_->send_buffer_capacity() - send_buffer_.size();
+  if (0 == capacity) {
+    ready_to_send_ = false;
+    error_ = EWOULDBLOCK;
+    return -1;
+  }
+  size_t consumed = std::min(cb, capacity);
+  const char* cpv = static_cast<const char*>(pv);
+  send_buffer_.insert(send_buffer_.end(), cpv, cpv + consumed);
+  server_->SendTcp(this);
+  return static_cast<int>(consumed);
+}
+
+void VirtualSocket::OnSocketServerReadyToSend() {
+  if (ready_to_send_) {
+    // This socket didn't encounter EWOULDBLOCK, so there's nothing to do.
+    return;
+  }
+  if (type_ == SOCK_DGRAM) {
+    ready_to_send_ = true;
+    SignalWriteEvent(this);
+  } else {
+    RTC_DCHECK(type_ == SOCK_STREAM);
+    // This will attempt to empty the full send buffer, and will fire
+    // SignalWriteEvent if successful.
+    server_->SendTcp(this);
+  }
+}
+
+void VirtualSocket::SetToBlocked() {
+  ready_to_send_ = false;
+  error_ = EWOULDBLOCK;
+}
+
+void VirtualSocket::UpdateRecv(size_t data_size) {
+  recv_buffer_size_ += data_size;
+}
+
+void VirtualSocket::UpdateSend(size_t data_size) {
+  size_t new_buffer_size = send_buffer_.size() - data_size;
+  // Avoid undefined access beyond the last element of the vector.
+  // This only happens when new_buffer_size is 0.
+  if (data_size < send_buffer_.size()) {
+    // memmove is required for potentially overlapping source/destination.
+    memmove(&send_buffer_[0], &send_buffer_[data_size], new_buffer_size);
+  }
+  send_buffer_.resize(new_buffer_size);
+}
+
+void VirtualSocket::MaybeSignalWriteEvent(size_t capacity) {
+  if (!ready_to_send_ && (send_buffer_.size() < capacity)) {
+    ready_to_send_ = true;
+    SignalWriteEvent(this);
+  }
+}
+
+uint32_t VirtualSocket::AddPacket(int64_t cur_time, size_t packet_size) {
+  network_size_ += packet_size;
+  uint32_t send_delay =
+      server_->SendDelay(static_cast<uint32_t>(network_size_));
+
+  NetworkEntry entry;
+  entry.size = packet_size;
+  entry.done_time = cur_time + send_delay;
+  network_.push_back(entry);
+
+  return send_delay;
+}
+
+int64_t VirtualSocket::UpdateOrderedDelivery(int64_t ts) {
+  // Ensure that new packets arrive after previous ones
+  ts = std::max(ts, last_delivery_time_);
+  // A socket should not have both ordered and unordered delivery, so its last
+  // delivery time only needs to be updated when it has ordered delivery.
+  last_delivery_time_ = ts;
+  return ts;
+}
+
+size_t VirtualSocket::PurgeNetworkPackets(int64_t cur_time) {
+  while (!network_.empty() && (network_.front().done_time <= cur_time)) {
+    RTC_DCHECK(network_size_ >= network_.front().size);
+    network_size_ -= network_.front().size;
+    network_.pop_front();
+  }
+  return network_size_;
+}
+
+VirtualSocketServer::VirtualSocketServer() : VirtualSocketServer(nullptr) {}
+
+VirtualSocketServer::VirtualSocketServer(ThreadProcessingFakeClock* fake_clock)
+    : fake_clock_(fake_clock),
+      msg_queue_(nullptr),
+      stop_on_idle_(false),
+      next_ipv4_(kInitialNextIPv4),
+      next_ipv6_(kInitialNextIPv6),
+      next_port_(kFirstEphemeralPort),
+      bindings_(new AddressMap()),
+      connections_(new ConnectionMap()),
+      bandwidth_(0),
+      network_capacity_(kDefaultNetworkCapacity),
+      send_buffer_capacity_(kDefaultTcpBufferSize),
+      recv_buffer_capacity_(kDefaultTcpBufferSize),
+      delay_mean_(0),
+      delay_stddev_(0),
+      delay_samples_(NUM_SAMPLES),
+      drop_prob_(0.0) {
+  UpdateDelayDistribution();
+}
+
+VirtualSocketServer::~VirtualSocketServer() {
+  delete bindings_;
+  delete connections_;
+}
+
+IPAddress VirtualSocketServer::GetNextIP(int family) {
+  if (family == AF_INET) {
+    IPAddress next_ip(next_ipv4_);
+    next_ipv4_.s_addr = HostToNetwork32(NetworkToHost32(next_ipv4_.s_addr) + 1);
+    return next_ip;
+  } else if (family == AF_INET6) {
+    IPAddress next_ip(next_ipv6_);
+    uint32_t* as_ints = reinterpret_cast<uint32_t*>(&next_ipv6_.s6_addr);
+    as_ints[3] += 1;
+    return next_ip;
+  }
+  return IPAddress();
+}
+
+uint16_t VirtualSocketServer::GetNextPort() {
+  uint16_t port = next_port_;
+  if (next_port_ < kLastEphemeralPort) {
+    ++next_port_;
+  } else {
+    next_port_ = kFirstEphemeralPort;
+  }
+  return port;
+}
+
+void VirtualSocketServer::SetSendingBlocked(bool blocked) {
+  {
+    webrtc::MutexLock lock(&mutex_);
+    if (blocked == sending_blocked_) {
+      // Unchanged; nothing to do.
+      return;
+    }
+    sending_blocked_ = blocked;
+  }
+  if (!blocked) {
+    // Sending was blocked, but is now unblocked. This signal gives sockets a
+    // chance to fire SignalWriteEvent, and for TCP, send buffered data.
+    SignalReadyToSend();
+  }
+}
+
+VirtualSocket* VirtualSocketServer::CreateSocket(int family, int type) {
+  return new VirtualSocket(this, family, type);
+}
+
+void VirtualSocketServer::SetMessageQueue(Thread* msg_queue) {
+  msg_queue_ = msg_queue;
+}
+
+bool VirtualSocketServer::Wait(webrtc::TimeDelta max_wait_duration,
+                               bool process_io) {
+  RTC_DCHECK_RUN_ON(msg_queue_);
+  if (stop_on_idle_ && Thread::Current()->empty()) {
+    return false;
+  }
+  // Note: we don't need to do anything with `process_io` since we don't have
+  // any real I/O. Received packets come in the form of queued messages, so
+  // Thread will ensure WakeUp is called if another thread sends a
+  // packet.
+  wakeup_.Wait(max_wait_duration);
+  return true;
+}
+
+void VirtualSocketServer::WakeUp() {
+  wakeup_.Set();
+}
+
+void VirtualSocketServer::SetAlternativeLocalAddress(
+    const rtc::IPAddress& address,
+    const rtc::IPAddress& alternative) {
+  alternative_address_mapping_[address] = alternative;
+}
+
+bool VirtualSocketServer::ProcessMessagesUntilIdle() {
+  RTC_DCHECK_RUN_ON(msg_queue_);
+  stop_on_idle_ = true;
+  while (!msg_queue_->empty()) {
+    if (fake_clock_) {
+      // If using a fake clock, advance it in millisecond increments until the
+      // queue is empty.
+      fake_clock_->AdvanceTime(webrtc::TimeDelta::Millis(1));
+    } else {
+      // Otherwise, run a normal message loop.
+      msg_queue_->ProcessMessages(Thread::kForever);
+    }
+  }
+  stop_on_idle_ = false;
+  return !msg_queue_->IsQuitting();
+}
+
+void VirtualSocketServer::SetNextPortForTesting(uint16_t port) {
+  next_port_ = port;
+}
+
+bool VirtualSocketServer::CloseTcpConnections(
+    const SocketAddress& addr_local,
+    const SocketAddress& addr_remote) {
+  VirtualSocket* socket = LookupConnection(addr_local, addr_remote);
+  if (!socket) {
+    return false;
+  }
+  // Signal the close event on the local connection first.
+  socket->SignalCloseEvent(socket, 0);
+
+  // Trigger the remote connection's close event.
+  socket->Close();
+
+  return true;
+}
+
+int VirtualSocketServer::Bind(VirtualSocket* socket,
+                              const SocketAddress& addr) {
+  RTC_DCHECK(nullptr != socket);
+  // Address must be completely specified at this point
+  RTC_DCHECK(!IPIsUnspec(addr.ipaddr()));
+  RTC_DCHECK(addr.port() != 0);
+
+  // Normalize the address (turns v6-mapped addresses into v4-addresses).
+  SocketAddress normalized(addr.ipaddr().Normalized(), addr.port());
+
+  AddressMap::value_type entry(normalized, socket);
+  return bindings_->insert(entry).second ? 0 : -1;
+}
+
+SocketAddress VirtualSocketServer::AssignBindAddress(
+    const SocketAddress& app_addr) {
+  RTC_DCHECK(!IPIsUnspec(app_addr.ipaddr()));
+
+  // Normalize the IP.
+  SocketAddress addr;
+  addr.SetIP(app_addr.ipaddr().Normalized());
+
+  // If the IP appears in `alternative_address_mapping_`, meaning the test has
+  // configured sockets bound to this IP to actually use another IP, replace
+  // the IP here.
+  auto alternative = alternative_address_mapping_.find(addr.ipaddr());
+  if (alternative != alternative_address_mapping_.end()) {
+    addr.SetIP(alternative->second);
+  }
+
+  if (app_addr.port() != 0) {
+    addr.SetPort(app_addr.port());
+  } else {
+    // Assign a port.
+    for (int i = 0; i < kEphemeralPortCount; ++i) {
+      addr.SetPort(GetNextPort());
+      if (bindings_->find(addr) == bindings_->end()) {
+        break;
+      }
+    }
+  }
+
+  return addr;
+}
+
+VirtualSocket* VirtualSocketServer::LookupBinding(const SocketAddress& addr) {
+  SocketAddress normalized(addr.ipaddr().Normalized(), addr.port());
+  AddressMap::iterator it = bindings_->find(normalized);
+  if (it != bindings_->end()) {
+    return it->second;
+  }
+
+  IPAddress default_ip = GetDefaultSourceAddress(addr.ipaddr().family());
+  if (!IPIsUnspec(default_ip) && addr.ipaddr() == default_ip) {
+    // If we can't find a binding for the packet which is sent to the interface
+    // corresponding to the default route, it should match a binding with the
+    // correct port to the any address.
+    SocketAddress sock_addr =
+        EmptySocketAddressWithFamily(addr.ipaddr().family());
+    sock_addr.SetPort(addr.port());
+    return LookupBinding(sock_addr);
+  }
+
+  return nullptr;
+}
+
+int VirtualSocketServer::Unbind(const SocketAddress& addr,
+                                VirtualSocket* socket) {
+  SocketAddress normalized(addr.ipaddr().Normalized(), addr.port());
+  RTC_DCHECK((*bindings_)[normalized] == socket);
+  bindings_->erase(bindings_->find(normalized));
+  return 0;
+}
+
+void VirtualSocketServer::AddConnection(const SocketAddress& local,
+                                        const SocketAddress& remote,
+                                        VirtualSocket* remote_socket) {
+  // Add this socket pair to our routing table. This will allow
+  // multiple clients to connect to the same server address.
+  SocketAddress local_normalized(local.ipaddr().Normalized(), local.port());
+  SocketAddress remote_normalized(remote.ipaddr().Normalized(), remote.port());
+  SocketAddressPair address_pair(local_normalized, remote_normalized);
+  connections_->insert(std::pair<SocketAddressPair, VirtualSocket*>(
+      address_pair, remote_socket));
+}
+
+VirtualSocket* VirtualSocketServer::LookupConnection(
+    const SocketAddress& local,
+    const SocketAddress& remote) {
+  SocketAddress local_normalized(local.ipaddr().Normalized(), local.port());
+  SocketAddress remote_normalized(remote.ipaddr().Normalized(), remote.port());
+  SocketAddressPair address_pair(local_normalized, remote_normalized);
+  ConnectionMap::iterator it = connections_->find(address_pair);
+  return (connections_->end() != it) ? it->second : nullptr;
+}
+
+void VirtualSocketServer::RemoveConnection(const SocketAddress& local,
+                                           const SocketAddress& remote) {
+  SocketAddress local_normalized(local.ipaddr().Normalized(), local.port());
+  SocketAddress remote_normalized(remote.ipaddr().Normalized(), remote.port());
+  SocketAddressPair address_pair(local_normalized, remote_normalized);
+  connections_->erase(address_pair);
+}
+
+static double Random() {
+  return static_cast<double>(rand()) / RAND_MAX;
+}
+
+int VirtualSocketServer::Connect(VirtualSocket* socket,
+                                 const SocketAddress& remote_addr,
+                                 bool use_delay) {
+  RTC_DCHECK(msg_queue_);
+
+  TimeDelta delay = TimeDelta::Millis(use_delay ? GetTransitDelay(socket) : 0);
+  VirtualSocket* remote = LookupBinding(remote_addr);
+  if (!CanInteractWith(socket, remote)) {
+    RTC_LOG(LS_INFO) << "Address family mismatch between "
+                     << socket->GetLocalAddress().ToString() << " and "
+                     << remote_addr.ToString();
+    return -1;
+  }
+  if (remote != nullptr) {
+    remote->PostConnect(delay, socket->GetLocalAddress());
+  } else {
+    RTC_LOG(LS_INFO) << "No one listening at " << remote_addr.ToString();
+    socket->PostDisconnect(delay);
+  }
+  return 0;
+}
+
+bool VirtualSocketServer::Disconnect(VirtualSocket* socket) {
+  if (!socket || !msg_queue_)
+    return false;
+
+  // If we simulate packets being delayed, we should simulate the
+  // equivalent of a FIN being delayed as well.
+  socket->PostDisconnect(TimeDelta::Millis(GetTransitDelay(socket)));
+  return true;
+}
+
+bool VirtualSocketServer::Disconnect(const SocketAddress& addr) {
+  return Disconnect(LookupBinding(addr));
+}
+
+bool VirtualSocketServer::Disconnect(const SocketAddress& local_addr,
+                                     const SocketAddress& remote_addr) {
+  // Disconnect remote socket, check if it is a child of a server socket.
+  VirtualSocket* socket = LookupConnection(local_addr, remote_addr);
+  if (!socket) {
+    // Not a server socket child, then see if it is bound.
+    // TODO(tbd): If this is indeed a server socket that has no
+    // children this will cause the server socket to be
+    // closed. This might lead to unexpected results, how to fix this?
+    socket = LookupBinding(remote_addr);
+  }
+  Disconnect(socket);
+
+  // Remove mapping for both directions.
+  RemoveConnection(remote_addr, local_addr);
+  RemoveConnection(local_addr, remote_addr);
+  return socket != nullptr;
+}
+
+int VirtualSocketServer::SendUdp(VirtualSocket* socket,
+                                 const char* data,
+                                 size_t data_size,
+                                 const SocketAddress& remote_addr) {
+  {
+    webrtc::MutexLock lock(&mutex_);
+    ++sent_packets_;
+    if (sending_blocked_) {
+      socket->SetToBlocked();
+      return -1;
+    }
+
+    // See if we want to drop this packet.
+    if (data_size > max_udp_payload_) {
+      RTC_LOG(LS_VERBOSE) << "Dropping too large UDP payload of size "
+                          << data_size << ", UDP payload limit is "
+                          << max_udp_payload_;
+      // Return as if send was successful; packet disappears.
+      return data_size;
+    }
+
+    if (Random() < drop_prob_) {
+      RTC_LOG(LS_VERBOSE) << "Dropping packet: bad luck";
+      return static_cast<int>(data_size);
+    }
+  }
+
+  VirtualSocket* recipient = LookupBinding(remote_addr);
+  if (!recipient) {
+    // Make a fake recipient for address family checking.
+    std::unique_ptr<VirtualSocket> dummy_socket(
+        CreateSocket(AF_INET, SOCK_DGRAM));
+    dummy_socket->SetLocalAddress(remote_addr);
+    if (!CanInteractWith(socket, dummy_socket.get())) {
+      RTC_LOG(LS_VERBOSE) << "Incompatible address families: "
+                          << socket->GetLocalAddress().ToString() << " and "
+                          << remote_addr.ToString();
+      return -1;
+    }
+    RTC_LOG(LS_VERBOSE) << "No one listening at " << remote_addr.ToString();
+    return static_cast<int>(data_size);
+  }
+
+  if (!CanInteractWith(socket, recipient)) {
+    RTC_LOG(LS_VERBOSE) << "Incompatible address families: "
+                        << socket->GetLocalAddress().ToString() << " and "
+                        << remote_addr.ToString();
+    return -1;
+  }
+
+  {
+    int64_t cur_time = TimeMillis();
+    size_t network_size = socket->PurgeNetworkPackets(cur_time);
+
+    // Determine whether we have enough bandwidth to accept this packet.  To do
+    // this, we need to update the send queue.  Once we know it's current size,
+    // we know whether we can fit this packet.
+    //
+    // NOTE: There are better algorithms for maintaining such a queue (such as
+    // "Derivative Random Drop"); however, this algorithm is a more accurate
+    // simulation of what a normal network would do.
+    {
+      webrtc::MutexLock lock(&mutex_);
+      size_t packet_size = data_size + UDP_HEADER_SIZE;
+      if (network_size + packet_size > network_capacity_) {
+        RTC_LOG(LS_VERBOSE) << "Dropping packet: network capacity exceeded";
+        return static_cast<int>(data_size);
+      }
+    }
+
+    AddPacketToNetwork(socket, recipient, cur_time, data, data_size,
+                       UDP_HEADER_SIZE, false);
+
+    return static_cast<int>(data_size);
+  }
+}
+
+void VirtualSocketServer::SendTcp(VirtualSocket* socket) {
+  {
+    webrtc::MutexLock lock(&mutex_);
+    ++sent_packets_;
+    if (sending_blocked_) {
+      // Eventually the socket's buffer will fill and VirtualSocket::SendTcp
+      // will set EWOULDBLOCK.
+      return;
+    }
+  }
+
+  // TCP can't send more data than will fill up the receiver's buffer.
+  // We track the data that is in the buffer plus data in flight using the
+  // recipient's recv_buffer_size_.  Anything beyond that must be stored in the
+  // sender's buffer.  We will trigger the buffered data to be sent when data
+  // is read from the recv_buffer.
+
+  // Lookup the local/remote pair in the connections table.
+  VirtualSocket* recipient =
+      LookupConnection(socket->GetLocalAddress(), socket->GetRemoteAddress());
+  if (!recipient) {
+    RTC_LOG(LS_VERBOSE) << "Sending data to no one.";
+    return;
+  }
+
+  int64_t cur_time = TimeMillis();
+  socket->PurgeNetworkPackets(cur_time);
+
+  while (true) {
+    size_t available = recv_buffer_capacity() - recipient->recv_buffer_size();
+    size_t max_data_size =
+        std::min<size_t>(available, TCP_MSS - TCP_HEADER_SIZE);
+    size_t data_size = std::min(socket->send_buffer_size(), max_data_size);
+    if (0 == data_size)
+      break;
+
+    AddPacketToNetwork(socket, recipient, cur_time, socket->send_buffer_data(),
+                       data_size, TCP_HEADER_SIZE, true);
+    recipient->UpdateRecv(data_size);
+    socket->UpdateSend(data_size);
+  }
+
+  socket->MaybeSignalWriteEvent(send_buffer_capacity());
+}
+
+void VirtualSocketServer::SendTcp(const SocketAddress& addr) {
+  VirtualSocket* sender = LookupBinding(addr);
+  RTC_DCHECK(nullptr != sender);
+  SendTcp(sender);
+}
+
+void VirtualSocketServer::AddPacketToNetwork(VirtualSocket* sender,
+                                             VirtualSocket* recipient,
+                                             int64_t cur_time,
+                                             const char* data,
+                                             size_t data_size,
+                                             size_t header_size,
+                                             bool ordered) {
+  RTC_DCHECK(msg_queue_);
+  uint32_t send_delay = sender->AddPacket(cur_time, data_size + header_size);
+
+  // Find the delay for crossing the many virtual hops of the network.
+  uint32_t transit_delay = GetTransitDelay(sender);
+
+  // When the incoming packet is from a binding of the any address, translate it
+  // to the default route here such that the recipient will see the default
+  // route.
+  SocketAddress sender_addr = sender->GetLocalAddress();
+  IPAddress default_ip = GetDefaultSourceAddress(sender_addr.ipaddr().family());
+  if (sender_addr.IsAnyIP() && !IPIsUnspec(default_ip)) {
+    sender_addr.SetIP(default_ip);
+  }
+
+  int64_t ts = cur_time + send_delay + transit_delay;
+  if (ordered) {
+    ts = sender->UpdateOrderedDelivery(ts);
+  }
+  recipient->PostPacket(TimeDelta::Millis(ts - cur_time),
+                        std::make_unique<Packet>(data, data_size, sender_addr));
+}
+
+uint32_t VirtualSocketServer::SendDelay(uint32_t size) {
+  webrtc::MutexLock lock(&mutex_);
+  if (bandwidth_ == 0)
+    return 0;
+  else
+    return 1000 * size / bandwidth_;
+}
+
+#if 0
+void PrintFunction(std::vector<std::pair<double, double> >* f) {
+  return;
+  double sum = 0;
+  for (uint32_t i = 0; i < f->size(); ++i) {
+    std::cout << (*f)[i].first << '\t' << (*f)[i].second << std::endl;
+    sum += (*f)[i].second;
+  }
+  if (!f->empty()) {
+    const double mean = sum / f->size();
+    double sum_sq_dev = 0;
+    for (uint32_t i = 0; i < f->size(); ++i) {
+      double dev = (*f)[i].second - mean;
+      sum_sq_dev += dev * dev;
+    }
+    std::cout << "Mean = " << mean << " StdDev = "
+              << sqrt(sum_sq_dev / f->size()) << std::endl;
+  }
+}
+#endif  // <unused>
+
+void VirtualSocketServer::UpdateDelayDistribution() {
+  webrtc::MutexLock lock(&mutex_);
+  delay_dist_ = CreateDistribution(delay_mean_, delay_stddev_, delay_samples_);
+}
+
+static double PI = 4 * atan(1.0);
+
+static double Normal(double x, double mean, double stddev) {
+  double a = (x - mean) * (x - mean) / (2 * stddev * stddev);
+  return exp(-a) / (stddev * sqrt(2 * PI));
+}
+
+#if 0  // static unused gives a warning
+static double Pareto(double x, double min, double k) {
+  if (x < min)
+    return 0;
+  else
+    return k * std::pow(min, k) / std::pow(x, k+1);
+}
+#endif
+
+std::unique_ptr<VirtualSocketServer::Function>
+VirtualSocketServer::CreateDistribution(uint32_t mean,
+                                        uint32_t stddev,
+                                        uint32_t samples) {
+  auto f = std::make_unique<Function>();
+
+  if (0 == stddev) {
+    f->push_back(Point(mean, 1.0));
+  } else {
+    double start = 0;
+    if (mean >= 4 * static_cast<double>(stddev))
+      start = mean - 4 * static_cast<double>(stddev);
+    double end = mean + 4 * static_cast<double>(stddev);
+
+    for (uint32_t i = 0; i < samples; i++) {
+      double x = start + (end - start) * i / (samples - 1);
+      double y = Normal(x, mean, stddev);
+      f->push_back(Point(x, y));
+    }
+  }
+  return Resample(Invert(Accumulate(std::move(f))), 0, 1, samples);
+}
+
+uint32_t VirtualSocketServer::GetTransitDelay(Socket* socket) {
+  // Use the delay based on the address if it is set.
+  auto iter = delay_by_ip_.find(socket->GetLocalAddress().ipaddr());
+  if (iter != delay_by_ip_.end()) {
+    return static_cast<uint32_t>(iter->second);
+  }
+  // Otherwise, use the delay from the distribution distribution.
+  size_t index = rand() % delay_dist_->size();
+  double delay = (*delay_dist_)[index].second;
+  // RTC_LOG_F(LS_INFO) << "random[" << index << "] = " << delay;
+  return static_cast<uint32_t>(delay);
+}
+
+struct FunctionDomainCmp {
+  bool operator()(const VirtualSocketServer::Point& p1,
+                  const VirtualSocketServer::Point& p2) {
+    return p1.first < p2.first;
+  }
+  bool operator()(double v1, const VirtualSocketServer::Point& p2) {
+    return v1 < p2.first;
+  }
+  bool operator()(const VirtualSocketServer::Point& p1, double v2) {
+    return p1.first < v2;
+  }
+};
+
+std::unique_ptr<VirtualSocketServer::Function> VirtualSocketServer::Accumulate(
+    std::unique_ptr<Function> f) {
+  RTC_DCHECK(f->size() >= 1);
+  double v = 0;
+  for (Function::size_type i = 0; i < f->size() - 1; ++i) {
+    double dx = (*f)[i + 1].first - (*f)[i].first;
+    double avgy = ((*f)[i + 1].second + (*f)[i].second) / 2;
+    (*f)[i].second = v;
+    v = v + dx * avgy;
+  }
+  (*f)[f->size() - 1].second = v;
+  return f;
+}
+
+std::unique_ptr<VirtualSocketServer::Function> VirtualSocketServer::Invert(
+    std::unique_ptr<Function> f) {
+  for (Function::size_type i = 0; i < f->size(); ++i)
+    std::swap((*f)[i].first, (*f)[i].second);
+
+  absl::c_sort(*f, FunctionDomainCmp());
+  return f;
+}
+
+std::unique_ptr<VirtualSocketServer::Function> VirtualSocketServer::Resample(
+    std::unique_ptr<Function> f,
+    double x1,
+    double x2,
+    uint32_t samples) {
+  auto g = std::make_unique<Function>();
+
+  for (size_t i = 0; i < samples; i++) {
+    double x = x1 + (x2 - x1) * i / (samples - 1);
+    double y = Evaluate(f.get(), x);
+    g->push_back(Point(x, y));
+  }
+
+  return g;
+}
+
+double VirtualSocketServer::Evaluate(const Function* f, double x) {
+  Function::const_iterator iter =
+      absl::c_lower_bound(*f, x, FunctionDomainCmp());
+  if (iter == f->begin()) {
+    return (*f)[0].second;
+  } else if (iter == f->end()) {
+    RTC_DCHECK(f->size() >= 1);
+    return (*f)[f->size() - 1].second;
+  } else if (iter->first == x) {
+    return iter->second;
+  } else {
+    double x1 = (iter - 1)->first;
+    double y1 = (iter - 1)->second;
+    double x2 = iter->first;
+    double y2 = iter->second;
+    return y1 + (y2 - y1) * (x - x1) / (x2 - x1);
+  }
+}
+
+bool VirtualSocketServer::CanInteractWith(VirtualSocket* local,
+                                          VirtualSocket* remote) {
+  if (!local || !remote) {
+    return false;
+  }
+  IPAddress local_ip = local->GetLocalAddress().ipaddr();
+  IPAddress remote_ip = remote->GetLocalAddress().ipaddr();
+  IPAddress local_normalized = local_ip.Normalized();
+  IPAddress remote_normalized = remote_ip.Normalized();
+  // Check if the addresses are the same family after Normalization (turns
+  // mapped IPv6 address into IPv4 addresses).
+  // This will stop unmapped V6 addresses from talking to mapped V6 addresses.
+  if (local_normalized.family() == remote_normalized.family()) {
+    return true;
+  }
+
+  // If ip1 is IPv4 and ip2 is :: and ip2 is not IPV6_V6ONLY.
+  int remote_v6_only = 0;
+  remote->GetOption(Socket::OPT_IPV6_V6ONLY, &remote_v6_only);
+  if (local_ip.family() == AF_INET && !remote_v6_only && IPIsAny(remote_ip)) {
+    return true;
+  }
+  // Same check, backwards.
+  int local_v6_only = 0;
+  local->GetOption(Socket::OPT_IPV6_V6ONLY, &local_v6_only);
+  if (remote_ip.family() == AF_INET && !local_v6_only && IPIsAny(local_ip)) {
+    return true;
+  }
+
+  // Check to see if either socket was explicitly bound to IPv6-any.
+  // These sockets can talk with anyone.
+  if (local_ip.family() == AF_INET6 && local->was_any()) {
+    return true;
+  }
+  if (remote_ip.family() == AF_INET6 && remote->was_any()) {
+    return true;
+  }
+
+  return false;
+}
+
+IPAddress VirtualSocketServer::GetDefaultSourceAddress(int family) {
+  if (family == AF_INET) {
+    return default_source_address_v4_;
+  }
+  if (family == AF_INET6) {
+    return default_source_address_v6_;
+  }
+  return IPAddress();
+}
+void VirtualSocketServer::SetDefaultSourceAddress(const IPAddress& from_addr) {
+  RTC_DCHECK(!IPIsAny(from_addr));
+  if (from_addr.family() == AF_INET) {
+    default_source_address_v4_ = from_addr;
+  } else if (from_addr.family() == AF_INET6) {
+    default_source_address_v6_ = from_addr;
+  }
+}
+
+void VirtualSocketServer::set_bandwidth(uint32_t bandwidth) {
+  webrtc::MutexLock lock(&mutex_);
+  bandwidth_ = bandwidth;
+}
+void VirtualSocketServer::set_network_capacity(uint32_t capacity) {
+  webrtc::MutexLock lock(&mutex_);
+  network_capacity_ = capacity;
+}
+
+uint32_t VirtualSocketServer::send_buffer_capacity() const {
+  webrtc::MutexLock lock(&mutex_);
+  return send_buffer_capacity_;
+}
+void VirtualSocketServer::set_send_buffer_capacity(uint32_t capacity) {
+  webrtc::MutexLock lock(&mutex_);
+  send_buffer_capacity_ = capacity;
+}
+
+uint32_t VirtualSocketServer::recv_buffer_capacity() const {
+  webrtc::MutexLock lock(&mutex_);
+  return recv_buffer_capacity_;
+}
+void VirtualSocketServer::set_recv_buffer_capacity(uint32_t capacity) {
+  webrtc::MutexLock lock(&mutex_);
+  recv_buffer_capacity_ = capacity;
+}
+
+void VirtualSocketServer::set_delay_mean(uint32_t delay_mean) {
+  webrtc::MutexLock lock(&mutex_);
+  delay_mean_ = delay_mean;
+}
+void VirtualSocketServer::set_delay_stddev(uint32_t delay_stddev) {
+  webrtc::MutexLock lock(&mutex_);
+  delay_stddev_ = delay_stddev;
+}
+void VirtualSocketServer::set_delay_samples(uint32_t delay_samples) {
+  webrtc::MutexLock lock(&mutex_);
+  delay_samples_ = delay_samples;
+}
+
+void VirtualSocketServer::set_drop_probability(double drop_prob) {
+  RTC_DCHECK_GE(drop_prob, 0.0);
+  RTC_DCHECK_LE(drop_prob, 1.0);
+
+  webrtc::MutexLock lock(&mutex_);
+  drop_prob_ = drop_prob;
+}
+
+void VirtualSocketServer::set_max_udp_payload(size_t payload_size) {
+  webrtc::MutexLock lock(&mutex_);
+  max_udp_payload_ = payload_size;
+}
+
+uint32_t VirtualSocketServer::sent_packets() const {
+  webrtc::MutexLock lock(&mutex_);
+  return sent_packets_;
+}
+
+}  // namespace rtc